I personally think that they are overpresribed. After working in services, I truly don't believe we can medicate away the effects of things like trauma, bereavement, etc. I think the best antidepressants do in these situations is put a plaster over a wound and balance you out enough to engage in therapy.
The issue is that long term therapy (which is what most people with trauma need) is not available on the NHS. CBT in my experience is also not adequate for trauma. I say this as both a MH professional and as someone who has had years of psychodynamic therapy for trauma.
Sexual dysfunction is actually a well known side effect of SSRIs, and that's really up to the patient whether the benefits outweigh the cons. The problem with antidepressants is that it's hard to measure as the benefits are very subjective.
Antipsychotics are a bit more clear cut, as the outcome is a reduction in psychotic symptoms. And when they work, they work very well.
Depression is caused by many things (genetic, your internal working model/how your psyche processes things/trauma/grief, etc) so it's harder to treat in some ways.
There just aren't real alternatives on the NHS. CBT is fine for mild anxiety. It is woefully inadequate for things like PTSD. So what other option, other than to prescribe and hope for the best?